Scientific paper ID 1884 : 2019/3

Hristo Hristov, Mariya Hristova

The concept of a dangerous failure in the safety critical system is defined. A task is set to analyze the probability of a dangerous failure within a widely popular class of safety critical systems known as structures.

In the context of system failures, a comparison is made between computer processing and telecommunication transmission of messages. It is known that impulse errors of the individual discharges are (assumed as) independent and the code distance D between the functional vectors is a means of efficient protection against interference during the linear transmission of information. With the increase in distance D the probability qD to transition to a wrong vector abruptly decreases. In computer processing, this security method does not work. Any failure in a microprocessor device, irrespective of its nature (hardware or software), may generate with equal probability all erroneous output vectors N = 2v, where n is the number of vector discharges. The study is performed with the assumption of this condition. Two groups of failures influence system security: Common-Mode Failure (CMF) and Accidental Non-Identification (ANI). This paper is a part of a more extensive research that covers both groups, and yet it focuses on the second type of causes – accidentally non-identified failures ANI. Formulas are elaborated for assessment of ANI dangerous failures and their probability depending on the length of the vectors.

критични по безопасност системи поведение на системите след отказ надеждност безопасност опасни откази.Safety Critical Systems system behaviour after failure reliability safety dangerous failures.Hristo Hristov Mariya Hristova


[1] Hristova M. Softuer za kritichni po bezopasnost sistemi: problemi i resheniya. Izdatelstvo VTU „Todor Kableshkov”, Sofiya, ISBN 978-954-12-0240-1, 2016
( [1] Христова М. Софтуер за критични по безопасност системи: проблеми и решения. Издателство ВТУ „Тодор Каблешков”, София, ISBN 978-954-12-0240-1, 2016 )

[2] Smith David J., K. GL Simpson.The Safety Critical Systems Handbook: A Straightforward Guide to Functional Safety: IEC 61511 (2016 Edition) & Related Guidance

[3] Popov G. N., M. E. Nenova, K. Raynova, Reliability Investigation of TMR and DMR Systems with Global and Partial Reservation, Published in Seventh Balkan Conference on Lightingh, DOI:10.1109/balkanlight.2018.8546926, 2018

[4] Lee P. A., T. Anderson. Fault Tolerance: Principles and Practice, Springer Scince&Business Media, pp. 51-62, 2012

[5] Hristov Hr., M. Hristova, COMPUTER CONTROL SYSTEMS WITH CRITICAL SAFETY APPLICATIONS: PROBLEMS AND SOME SOLUTIONS, Journal of Information Technology and Applications (JITA), ISSN 2232-9625 (PRINT), EISSN: 2233-0194 BANJA LUKA, JITA 7(2017) 2:61-68, vol. 7, issue 2, 2017

[6] Hristov H., W. Bo, Safety Critical Computer Systems: failure Independence and software diversity effects on Reliability of dual channel structures, Information Technologies and Control, № 2, pp. 9-18, 2014

[7] Popov G., Raynova K., Comparative dependability analysis of TMR and DMR systems with general and separate reservation, ITEO`2017, Information Technologies for E-Learning, PanEvropski Universitet Apeiron, Banja Luka, 29-30 Sept, ISBN 978-99976-34-13-9




This site uses cookies as they are important to its work.

Accept all cookies
Cookies Policy